Last month, her younger sister Emily Cho faced an uproar after she reportedly insulted an advertising executive and threw water in his face.

“As chairman of Korean Air and as the head of my family, I feel miserable by the immature behavior of my daughters,” Cho Yang-ho said in a statement Sunday. “I apologize to all Koreans.”

The younger sister had also apologized, saying what she did was “foolish,” but labor unions demanded she step down and be punished, and she is now reportedly under investigation by police over the incident.

During the incident, the then-40-year-old Heather Cho went berserk and screamed “loud and abusive language” from her first-class seat. Before he was kicked off the flight, the chief flight attendant said he was forced to kneel before Heather Cho, who oversaw in-flight services for the company, according to reports.

Chairman Cho said the company would “turn over a new leaf” with stronger management led by its board.